Minneapolis Plumbing Question- Min Drain Size

[Joseph Lee]

This is a pretty specific question, but can someone tell me the minimum drain size required for a kitchen sink in Minneapolis? We're renovating a kitchen and had one plumber tell us 2.0", while my code research (section 420.3) tells me it's 1.5". 

Our drain is currently 1.5", and I don't want to have to tear into the wall if it's not necessary and I don't want to have any surprises me it comes to the final inspection for our building permit. I also have trouble internallizing pulling a permit and hiring out the work for a simple sink hookup. 

Also, if anyone has any plumber recommendations  in the area, I'd appreciate them. Thanks!

[John Woodrich]

@Joseph Lee in regards to pulling the permit - I would first be surprised if the building inspector doesn't ask you about the plumbing permit.  Hopefully he does his job and gets out.  I haven't completed any plumbing upgrades in Mpls, only repairs so I haven't gone through the permit process on the plumbing side.  I thought the homeowner could pull a plumbing permit so long as they are living or intend to live in the property however Mpls may have further restrictions.

In my first few years of investing I operated under your thoughts - skipping a permit shouldn't matter, I know what I am doing and it won't get caught.  We learned the hard way on one flip back in the day and one plumbing inspector thought we did a lot of work we didn't do so we had to have a licensed plumber update areas of the house which were not touched to bring to current code.  That cost us around $5k of profit on a flip which was already active contingent.

At some point I realized if I want to make this a business I need to operate under the rules and not cut corners.  It does cost more but it does give you some piece of mind along with the future owners and inspectors when they see the permit history.  I am actually working on a house that I will move into, we are doing the normal kitchen, baths, etc.  I was planning on rewiring the kitchen myself as I can pull permits as the homeowner.  Now I am debating on just hiring it out to keep my relationship with my electrician going and so I don't have to deal with the hassles of meeting inspectors.

My mindset on this has taken a complete flip.  I personally don't understand why we have to pull permits for each sink install but the code requires you to update your system to code when you start working on it.  So to follow the rules you either have to leave it alone or not touch it.  The dumb part is that if you had a leak or corroded piping and had to replace the drain, it would be considered a repair and you wouldn't have to pull a permit....  Maybe that will help give you a reason around it.

The system may not make sense but it is there to protect everyone.